Clerk Stops Robbery, Gets Fired for Having a Gun

Imagine, if you will, a guy comes into a store you're a clerk at. He is armed with a hatchet and demands all the money in the cash register. You really have no idea what this person plans to do after he gets the money. Will he exit the store and run off, or will he hack you to death with the hatchet?

You have no idea, so you pull out your pistol and "game over".  I once worked in a liquor store in California and we kept a pistol under the counter. A cop that used to stop by the store would always tell us that if we shoot, "shoot to kill, less paperwork for the police".

Well this clerk pulled a gun and the robber surrendered. The problem here is that there was a company policy about having a firearm at work. Their official policy was to de-escalate the situation by complying with the robbers demands and hope he just runs off.

This clerk thought otherwise and was fired for having the gun at work. I guess I can understand the company policy but like I said before, you don't know what the robbers intentions are once he gets the money.

What would you do?